A flash memory cell is a type of non-volatile memory (NVM) cell that stores charge in a charge storage region, for example, a floating gate. The amount of charge on the floating gate determines a threshold voltage (VT) of the cell, hence the logic state stored by the cell. Each time the cell is programmed or erased, electrons are moved to or from the floating gate using a relatively high program or erasing voltage. The floating gate is electrically isolated so that charge is stored indefinitely. Non-volatile memory is commonly implemented, or embedded, on an integrated circuit that also includes logic circuits implemented with a conventional metal-oxide semiconductor (MOS) process. When embedding a non-volatile memory, such as for example, a flash memory having floating gate transistors, the embedded memory is formed using different manufacturing steps than the logic circuits. Frequently, the manufacturing process for the NVM that is embedded on an integrated circuit with logic circuits is not compatible with the manufacturing process used to form the logic circuit transistors. This is due in part because the logic circuits operate at a relatively lower voltage than the flash memory. In this case, one or both of the manufacturing processes must be changed. Also, as an integrated circuit manufacturing process advances, the minimum feature size of the devices on the integrated circuit may decrease. This reduction in minimum feature size, or scaling, may result in problems due to manufacturing process differences that did not cause a problem with the larger feature size.
Therefore, it is desirable to provide an integrated circuit having an embedded non-volatile memory without the above mentioned problems.